This invention relates to trucks of the type including a semitrailer that is pulled by a tractor and more particularly to a supplemental right turn signal especially adapted to be mounted for use on such a semitrailer.
Semitrailers are used for carrying all types of goods to wholesale and retail outlets located within a community. When parked at a site to be loaded or unloaded, the semitrailer is supported by wheels on the rear thereof and a pair of landing gears near the forward end thereof. When this semitrailer is to be moved, the rear of a tractor is pivotally attached to the forward end of the semitrailer and the pair of landing gears are telescopically shortened so that the forward end of the semitrailer is supported on the rear wheels of the tractor.
Inasmuch as the body of the semitrailer is a rather long and high box-like enclosure anchored on a similarly long chassis, the driver of the tractor must use undue caution in pulling the semitrailer around a right angled corner on a surface street such as at an intersection. In particular, since the tractor which is pivotally attached to the forward end of the semitrailer is much shorter than the semitrailer, the path of the tractor around the corner is much more of a curve than that of the semitrailer. Thus, it is necessary for the driver of the tractor to approach the intersection in the curb lane and then swing to the second lane, so that when he makes the right hand turn, the semitrailer can follow a path substantially corresponding to a chord of the curved path of the tractor. In other words, during the course of making the turn, the right side of the semitrailer makes a reentry into a portion of the area of the curb lane prior to again becoming aligned with the path of the tractor as it completes the turn and proceeds down the street.
While the semitrailer is in the second lane as the driver of the tractor slowly starts the turn, a motorist may be approaching in the curb lane and seeing that it is open opposite the semitrailer will advance his vehicle up to the intersection. It is to be noted that the motorist will advance his vehicle in this manner even though he may be made aware that the driver of the tractor is planning to make a right hand turn as evident by the blinking of the conventional right turn signal on the back of the semitrailer. What most motorists are not aware of is that as the tractor continues to advance around the corner, the adjacent right side of the semitrailer being pulled thereby will more inwardly into the curb lane and ram into their vehicle causing severe damage.
It should be appreciated that the trucker is seated on the left side of the cab of the tractor and although he has a right side view mirror on the cab which enables him to rearwardly view the area opposite the right side of the semitrailer when the latter is aligned with the tractor, once the tractor starts to make the turn, this side view mirror is of no use in this respect. Thus, the driver of the tractor continues his turn not knowing that a vehicle has entered into the curb lane in the area adjacent the right of the semitrailer, thereby resulting in the aforementioned collision.